News & Events
Oct
20
What is the function of Crystal Resonator in an Oscillation circuit? Few tips for oscillating circu
Content

What is the function of Quartz Crystal Resonator in an Oscillation circuit?

Few tips for oscillating circuit design

The function of quartz crystal resonator is locking and determines the oscillation frequency of an oscillating circuit which is widely used in electronic industrial. Proper circuit design and components configure is crucial to the stability of oscillating circuit with quartz crystal resonator overtime.

How can we know the oscillating circuit using crystal resonator is proper designed? What shall hardware engineers consider? Interquip Electronics, manufacturer of quartz crystal resonators and oscillators, would like to share some basic tips:

• Negative Resistance
• Drive Level
• On board oscillating frequency

Negative Resistance of the oscillating circuit

Negative resistance (-R) is a parameter of an oscillating circuit that determined by the gain and terminated capacitances which shall be large enough to ensure a reliable oscillation.

According to the basic rule, the negative feedback loop gain of an oscillation circuit shall be greater than 1 to sustain an oscillation. |-R| divided by Rr represent the negative gain of the oscillating circuit approximately. The recommendations from IEC60444-6 is |-R| / Rr shall be greater than or equal to 3 for reliable oscillation and Rr shall be the maximum Rr in all circumstances. Interquip Electronics recommends 5 times or more which has a better design margin.

The Drive Level of the oscillation circuit

Quartz crystal resonator is a piezoelectric device. The piezoelectric effect provides a coupling between the mechanical properties of a piezoelectric crystal and an electrical circuit. Below is the bulk acoustic wave mode of an AT cut quartz crystal resonator,

The mechanical displacement is proportional to the drive level (power) applied. It induces stress and cause irreversible damage over time in some circumstance if the drive level is extreme large. 1uW to 100uW is recommended for AT cut Mhz quartz crystal resonator in general.

The drive level is equal to,

DL=Ix2*RL

RL: Load resistance, which is equal to Rr(1+C0/CL)²

Ix: the current go thru the quartz crystal resonator

C0: Shunt capacitance of quartz crystal resonator

Ix is the current go thru the quartz crystal resonator which could be measured using a high-frequency current probe.

On board oscillation frequency

The on board oscillating frequency is determined by the quartz crystal resonator characteristic and the on board equivalent load capacitance. The on board equivalent load capacitance CPCB is related to Cg/Cd, terminal capacitance of the integrated circuit (CIC)and stray capacitance (Cs) on board as below:

CPCB= (Cg + CIC)×(Cd + CIC)/(Cg + Cd + 2 x CIC) + Cs

The quartz crystal resonator frequency is load capacitance (CL) depended. It is tuned by the manufacturer to the desired tolerance per specification. The on board oscillating frequency shall be within the frequency tolerance when the on board equivalent load capacitance is same as the CL specification of quartz crystal resonator. Otherwise, the on board oscillating frequency will deviate from the nominal frequency. If that happen, adjust Cg and Cd when necessary.

In addition, it shall be caution when measuring the on board oscillating frequency. The probe capacitance could be part of the on board equivalent load capacitance that contribute measurement error. A non-contact measurement using spectrum analyzer or equivalent is recommended.

In short, engineers shall verify the negative resistance of the oscillating circuit, the drive level and on-board oscillating frequency when the design of the oscillation circuit is determined. Adjust the circuit component to optimize the performance and lower the risk when necessary. Please feel free to contact Interquip Electronics if there is any question. You are always welcome.

Interquip Electronics is a comprehensive high-tech enterprise in R&D, manufacturing and marketing high precision Quartz Crystal Resonators (including self-developed material SMCM series, Thermistor Crystals and 32.768KHz Tuning Fork Crystals) and Oscillators (including TCXO, VCXO, LVDS/LVPECL output waveform SPXO, programmable Oscillators etc.). The size of crystal resonators and oscillators ranges from 1.2 x 1.0mm to 5.0 x3.2mm package, frequency available from 32.768KHz to 200MHz. The frequency components produced can be widely applied in 5G Smart Home, Smart Wear, IoT, IoV, Consumer Electronics, Telemedicine, Automotive Electronics (conforms to AEC-Q200), Communication Industry, Security Applications, Industrial Equipment and other industries.

Interquip Electronics Contact Information

Tel: +852 2413 5515

Fax: +852 2413 7053

Hong Kong Office: Flat A, 9th Floor, On Shing Industrial Building, 2-16 Wo Liu Hang Road, Fotan, N.T, Hong Kong SAR.

Factory Address: East of Bianxi River, South of Innovative Avenue, EBu Town, Shenshan Special Cooperation Zone, Shenzhen, Guangdong, China. 518200

Website:www.interquip.com

Oct
12
Interquip attended ES Show 2023 during Oct.11th to 13th
Content

Interquip attended ES Show 2023 during Oct.11th to 13th at Shenzhen World Exhibition & Convention Center.

You are very welcome to visit at our booth Hall 3, 3G21.

Sep
05
Interquip P-Series Programmable Oscillator
Content

The 163-P series SPXO is a programmable CMOS oscillator with AT cut resonator offering excellent temperature stability. The device programmable and operates from 1Mhz to 200Mhz according to customer request with supply voltage between 1.8 to 3.3Vdc. The device enables short lead time and meets the tight development schedule with its PLL technology which let your products get into the market shortly. Interquip is happy to work with you to win the market. Please contact us to learn more.

Specifications:

• Nominal Frequency: 1MHz~200MHz
• Output Waveform: CMOS
• Overall Frequency Stability: ±25ppm, ±30ppm or specify
• Supply Voltage Range(Vdd) : 1.8V ~ 3.3V
• Operating Temperature: -40°C ~ +85°C, -20°C ~ +70°C
• Start-up Time: 10ms Max.

Sep
05
Interquip will attend the 2023 ES Show during Oct. 11~13th
Content

Interquip will attend the 2023 ES Show during Oct. 11~13th at Shenzhen World Exhibition & Convention Center.

You are very welcome to visit at our booth Hall 3, 3G21.

Aug
17
Interquip 1610 Low ESR 32.768K Tuning Fork Crystal
Content

The ultra-miniature SMLF-1610 series of tuning fork crystals come in a 1.6 mm x 1.0 mm 2-pad ceramic package.

Specifications:

Nominal Frequency: 32.768KHz

Frequency Tolerance, Ta=25°C ± 3°C: ±20ppm

Load Capacitance: 5pF, 6pF, 7pF, 9pF, 12.5pF or specify

Operating Temperature: -20°C ~ +70°C, -40°C ~ +85°C

Equivalent Series Resistance (ESR): 90KΩ Max.

Aging: ±5ppm/Year Max.

Applications:

IoT, mobile devices, wearable devices and consumer electronics

May
18
Interquip Attended Smart Home Exhibition C-SMART 2023
Content

Interquip Attended Smart Home Exhibition C-SMART 2023 during May 16th to 18th at Shenzhen World Exhibition & Convention Center.

Apr
10
Interquip Attended China Information Technology Expo CITE 2023
Content

Interquip Attended China Information Technology Expo CITE 2023.

The show was held during April 7th to 9th at Shenzhen Convention & Exhibition Center.

Apr
03
Interquip will attend the 2023 CITE
Content

Interquip will attend the 2023 CITE during April 7th to 9th at Shenzhen Convention & Exhibition Center.

You are very welcome to visit at our booth Hall 1, 1A028.

Mar
31
Interquip Attended Asia Smart Wearable Expo
Content

Interquip Attended 2023 Asia Smart Wearable Expo during March 29th to 31th at Shenzhen Convention & Exhibition Center.

Mar
27
Interquip ultra-small Crystals for Wearables and Wireless Charging
Content

Interquip Electronics has its crystals of 1210, 1612, 2016 and 2520 applied in Wearables and Wireless Charging. The frequency control solutions include 32.768KHz, 24Mhz26Mhz32Mhz38.4Mhz40Mhz, and 52Mhz etc..

Mar
08
Interquip will attend 2023 Asia Smart Wearable Expo
Content

Interquip will attend 2023 Asia Smart Wearable Expo in Shenzhen during Mar. 29~31th, 2023.

You are very welcome to visit us at our Booth.

Show Time: Mar. 29~31th, 2023

Location: Shenzhen Convention & Exhibition Center (Futian District)

Interquip Booth No.: Hall 5, Booth B97